I used Paint.NET to create these, so it is recommended to use that program,
or use GIMP.
The fireball is a water balloon.

Use your 3DS to save a Mii's Face in Mii Maker to SD Card.
If you don't have a 3DS or 3DS XL, use this: http://www.miisearch.com/mii-creator.html
In the link above, Click the floppy button, then click Export, and uncheck Body, Shadow, Background.

In the Male or Female Template you downloaded, remove the 3 orange words on top of the template, Mii's Face of Death, Mii's Taunt Pose, Mii's Victory Pose.

Then look for an image of a Mii's face you saved, open the image, then place your Mii's face over the words, Mii's Face.